Commercial losses due to cattle and livestock pests, including the face, stable and horn flies, as well as other airborne pests, are well documented. Hall et al, J. Econ. Entomol., 82, pages 530-534 (1989) put the loss to the horn fly alone at an estimated $730.3 million dollars per year in the United States. The Hall reference documents a trap designed to permit the walk-through of cattle and other livestock, removing the flies from the livestock and trapping the flies in screen trapping elements. The trapping elements are accessible only from the interior of the walk-through trap. Similar traps were described as far back as 1938, Bruce, J. Kans. Ent. Soc., July, 1938. The Bruce design is discussed in the Hall article. Increases in the problems encountered in fly populations can be attributed, in part, to the use of straw and practice of feeding cattle hay from large rolled bails. The straw and rolled bails provide an ideal breeding medium for the stable fly. Thus, flies and similar airborne pests present an increasing and commercially significant problem for cattle and livestock farmers in the United States, as well as the rest of the world.
One typical response to this increased problem has been the use of increased insecticides. The use of insecticides has been widely documented as harmful to the environment, expensive, and ultimately ineffective, as resistance to each new insecticide is developed. An alternative method to control the pest problem is to design a fly trap which will effectively collect and destroy large portions of the fly population for any given herd or farm. Thus, U.S. Pat. No. 580,163, Richter, U.S. Pat. No. 642,399, White et al, U.S. Pat. No. 645,880, Varnum, U.S. Pat. No. 701,873, Gibson, U.S. Pat. No. 870,360, Harbuck are all older patents describing a wide variety of fly trapping means which permit a cow or other livestock to walk through a structure, the flies being removed from the cow while passing through the structure. Most of the early references use removable trap boxes to collect the flies, such as those set forth in U.S. Pat. No. 645,880, Varnum. U.S. Pat. No. 1,258,763, Girvin et al and U.S. Pat. No. 4,179,840, Sandefur, combine temporary structures with insecticidal means for addressing the fly pest problem. Other patents addressing a variety of walk-through fly trapping means include U.S. Pat. No. 1,260,339, Crockenberger, U.S. Pat. No. 1,312,130, Merrill et al, U.S. Pat. No. 2,141,545, which describes an illuminated trap as does U.S. Pat. No. 3,894,351, Iannini, which uses electric means for killing the collected insects. Another electric fly killing device is described in U.S. Pat. No. 4,300,306, Audgin, which is addressed to an electric screen which may be mounted in a field, but does not involve a walk-through trap. U.S. Pat. No. 5,205,063, Sutherist et al, describes a walk-through insect trap with transparent or translucent sides.
A hallmark of all the walk-through traps and related devices described in the prior art is that the trap or killing device is accessible only to insects on the interior of the trap, that is, insects brought into the trap or structure by the cattle. As many of the insects will not enter the trap with the cattle, kill rates are not sufficiently effective to reduce the commercial losses experienced.
Accordingly, it remains a pressing need in the art to provide a walk-through fly trap with fly killing means sufficient to increase the fly kill rate, and thereby provide a non-chemical dependent method of controlling the fly pest populations in livestock in the U.S. and around the world.